D&C 88: 1 – 47
Speaking of a house of order – all the universe is part of one kingdom or another. Each kingdom (save outer darkness which may be nothing more than a lack of kingdom) is associated with a level of law, light, and glory. All kingdoms except outer darkness are classified as being telestial, terrestrial, or celestial although there are many different degrees within the telestial and celestial kingdoms and thus we may reasonably assume that the same holds for the terrestrial kingdom.